Abstract

We have demonstrated a 10‐dB reduction in the intensity sidelobes of an apodized‐interaction‐strength guided‐wave acousto‐optic filter with a center passband of 1530 nm. Acoustic‐intensity weighting was achieved by launching a surface acoustic wave(SAW) beam in a straight acoustic waveguide, and gradually transferring this SAW intensity to the active device, and back out, by evanescent‐wave coupling across a 20 μm barrier over a 19‐mm interaction length. The intensity sidelobe was −5 dB for an unapodized filter with abrupt onset and cutoff of the interaction, but sidelobes were reduced to at most −15 dB for a SAW intensity with raised‐cosine weighting. A conversion efficiency of 97% was achieved with 80 mW input power for the 2.0‐nm‐wide apodized filter.